Hydraulic control

Abstract

Hydraulic control (1) comprising at least one hydraulic valve, each hydraulic valve comprising a hydraulic distributor (11) and an electric actuator (3). The hydraulic distributor comprises a valve slide (13) mounted with the ability to slide in a body (19) comprising hydraulic ports (17). The electric actuator is fixed to the body of the hydraulic distributor and comprises an electric motor (6), an electronic circuit (10) comprising a circuit board (24), a linear-displacement output member (4) coupled to the control slide, reduction gearing (8) comprising gear wheels (22) coupling the motor to the output member, and a housing (2) in which the electric motor (6), the electronic circuit (10) and the reduction gearing (8) are mounted.

Description

[0001] The present invention relates to the field of hydraulic controls, in particular comprising hydraulic valves, each comprising a hydraulic distributor and an electric actuator.

[0002] Hydraulic drives are used in many areas, for example in agricultural vehicles, construction machinery, cranes, and other lifting and handling equipment.

[0003] Some hydraulic controls comprise a plurality of juxtaposed hydraulic valves, each valve formed by a hydraulic distributor coupled to an electric actuator actuating a hydraulic control shaft, in particular a valve slide. An electric actuator for controlling hydraulic distributors is described for example in US patent 7,591,448.

[0004] The hydraulic valves of a hydraulic control are arranged in a juxtaposed manner, spaced by a distance that the actuators of the distributors must respect. The control axis of the hydraulic distributor is pushed by a pre-stressed spring which moves it into a safety position (so-called "position"). fail safe ") when the hydraulic system fails. To overcome the spring force and ensure highly dynamic operation, the actuator must provide high dynamic force.

[0005] Due to the demanding environment in which the actuator is used in many hydraulic applications, it is also important that the actuator is robust and reliable, able to withstand vibration, high temperature changes and shock.

[0006] The cost of the actuator is also an important factor.

[0007] It is also important to know the position of the control shaft accurately and reliably to ensure reliable operation.

[0008] The electric actuator described in US patent 7,591,448 is certainly compact and precise, however the production cost of such an actuator is high due to the number of components, the manufacturing cost of the components, and the complexity of the assembly.

[0009] An object of the invention is to provide a compact, high-performance, and reliable hydraulic control.

[0010] It is advantageous to provide a hydraulic control that is economical to manufacture.

[0011] A particular object of the invention is to provide a hydraulic control with a flat electric actuator for a hydraulic distributor, having a high torque density for its size and which is economical to manufacture.

[0012] Another object of the invention is to provide an electric actuator for hydraulic control, which is compact, efficient and reliable.

[0013] It is advantageous to provide an electric actuator for hydraulic control, having high efficiency.

[0014] An object of the invention is achieved by a hydraulic control according to the independent claim.

[0015] The dependent claims describe advantageous features of the invention. In the present invention, a hydraulic control is described comprising at least one hydraulic valve, each hydraulic valve comprising a hydraulic distributor and an electric actuator. The hydraulic distributor comprises a valve spool slidably mounted in a body comprising hydraulic channels. The electric actuator is attached to the body of the hydraulic distributor and comprises an electric motor, an electronic circuit comprising a circuit board, a linear displacement output member coupled to the control spool, a reduction gear comprising gear wheels coupling the motor to the output member, and a housing in which the electric motor, the electronic circuit and the reduction gear are mounted.

[0016] According to one aspect of the invention, the gear wheels include at least a first wheel and a second wheel, the second wheel being disposed on the side of a cover of the housing and the electric motor being mounted in the base of the housing. The first wheel includes a ring gear engaging a pinion of the rotor and a pinion engaging a ring gear of the second wheel. The circuit board is disposed between the ring gear of the second wheel and the magnet of the rotor of the electric motor.

[0017] The first wheel's crown gear is arranged at the height of the circuit board, in a cutout in the circuit board.

[0018] Advantageously, compared with a stepper motor used for actuating a hydraulic valve in conventional hydraulic controls, the use of a closed-loop controlled brushless DC motor makes it possible to transmit stronger force peaks to the valve slide and to work more safely, in particular by having high reliability in the positioning of the output member of the electric actuator.

[0019] It should be noted that a plurality of stacked or juxtaposed hydraulic distributors may comprise a common, single-piece body (comprising hydraulic channels), or a plurality of bodies (e.g., one per valve) assembled together.

[0020] Advantageously, the electric actuator according to the invention is very compact and in particular is characterized by one or more of the following ratios: an e / E ratio of a thickness e of the stator of the electric motor, including the winding thickness, to a thickness E of the electric actuator is greater than 0.45, the thickness measurement direction being a stacking or juxtaposition direction of the hydraulic valves forming the hydraulic control. an L / E ratio of a length L of the electric actuator to a thickness E of the electric actuator is greater than 2.5 and less than 4, the length measurement direction being orthogonal to a stacking direction of the hydraulic valves forming the hydraulic control and an actuation direction of the valve slide. an H / E ratio of a height H of the electric actuator to a thickness E of the electric actuator is greater than 2 and less than 3.5, the height measurement direction being the actuation direction of the valve slide.

[0021] The electric motor comprises a stator and a rotor, the rotor comprising a magnet defining a plurality of rotor poles and the stator comprising a magnetic armature and a plurality of coils mounted on the magnetic armature.

[0022] In an advantageous embodiment, the circuit board is arranged above an axial end of the rotor magnet, magnetic probes, for example Hall effect probes, being arranged on the circuit board above the magnetic segments of the magnet, the magnetic probes being arranged in an arc around the rotor at an angle (α) of less than 60 degrees.

[0023] In an advantageous embodiment, the rotor comprises a cylindrical magnet and a yoke arranged coaxially within the cylindrical magnet, the yoke and magnet being mounted in an overmolded plastic support, the support comprising flanges extending radially above the axial ends of the yoke and magnet.

[0024] The motor is a closed-loop controlled brushless DC motor.

[0025] In an advantageous embodiment, the coils are mounted on branches of the magnetic armature arranged in an arc of less than 180 degrees around the axis of rotation of the rotor, an axis of rotation of the first wheel of the reducer being mounted next to a part of the stator without coils.

[0026] In an advantageous embodiment, the second wheel comprises a position marker disposed on a face of the ring gear facing the circuit board and a position detector is mounted on the circuit board below the position marker.

[0027] In an advantageous embodiment, the position detector is in the form of a Hall effect sensor and the position marker is in the form of a ring magnet.

[0028] In an advantageous embodiment, the second wheel of the reducer comprises a pinion which engages a rack connected to the linear displacement output member.

[0029] In an advantageous embodiment, conductive wires of the coils are connected to electrical terminals formed from stamped parts inserted into or overmolded by a plastic material integrally forming the base of the housing and supporting the armature and the coils.

[0030] In an advantageous embodiment, the actuator comprises a connector for connecting the electronic circuit to an external control, a housing of the connector being integrally formed with the base of the housing, electrical terminals of the connector being overmolded in the base of the housing and comprising axially oriented connection portions for connection with the circuit board.

[0031] In an advantageous embodiment, the magnetic armature and the coils including electrical terminals for connection to a circuit board are overmolded in the plastic material forming the base of the housing.

[0032] In an advantageous embodiment, the clearance between the outer diameter of the yoke and the inner diameter of the magnet is in a range of 50 to 200 microns.

[0033] In an advantageous embodiment, the rotor support comprises a pinion integral with the support formed from an injected plastic material.

[0034] In one embodiment, the hydraulic control comprises a pre-stressed return spring acting on the valve spool. In a variant, the return spring is mounted at an interface between the body of the hydraulic distributor and the electric actuator, in a housing formed in the housing of the electric actuator.

[0035] Other objects and advantageous aspects of the invention will appear on reading the claims and / or the detailed description below of embodiments of the invention in relation to the figures, in which: There Fig. 1 is a perspective view of a hydraulic control according to a first embodiment of the invention; The Fig. 2 is a sectional view of the hydraulic control according to the Figure 1 ; There Fig. 3is a view of an electric actuator of the hydraulic control according to the Figure 1 ; There Fig. 4 is an exploded perspective view of the electric actuator according to the Figure 3 ; There Fig. 5 is a sectional view through the CC line of the actuator according to the Figure 3 ; There Fig. 6 is a sectional view through line EE of the actuator according to the Figure 3 ; There Fig. 7 is a sectional view through line DD of the actuator according to the Figure 3 ; There Fig. 7a is an enlarged view of part of the Figure 7 ; There Fig. 8 is a perspective view of a hydraulic control according to a second embodiment of the invention; The Fig. 9 is a sectional view of the hydraulic control according to the figure 8 ; There Fig. 10 is a view of an electric actuator of the hydraulic control according to the figure 8 ; There Fig. 11 is a sectional view through line AA of the actuator according to the Figure 10 ; There Fig. 12 is a sectional view through line BB of the actuator according to the Figure 10 ; There Fig. 13 is a sectional view of the actuator according to the Figure 10 ; There Fig. 14 is a perspective view of a rotor of an electric actuator of a hydraulic control according to an embodiment of the invention; The Fig. 15a is a perspective view of a stator of an electric actuator of a hydraulic control according to an embodiment of the invention; The Fig. 15b is a perspective view of a stator of an electric actuator of a hydraulic control according to one embodiment of the invention.

[0036] Referring to the figures, starting with the figures 1 , 2 , 8 And 9, a hydraulic control 1 comprises a plurality of hydraulic valves 11, 3 juxtaposed or stacked. Each hydraulic valve comprises a hydraulic distributor 11 and a corresponding electric actuator 3, a single electric actuator being associated with a single hydraulic distributor.

[0037] Each hydraulic valve comprises a valve spool 13 slidably mounted in a body 19 comprising hydraulic channels 17. The position and configuration of the hydraulic channels as well as the profile (not shown) of the valve spool are adapted to the hydraulic function and are known per se and will not be described in further detail herein. The number of juxtaposed valves forming the hydraulic control 1 may vary depending on the application. Given the stacked arrangement of the valves, there is an advantage in the distributors as well as the actuators having a small footprint in the direction of juxtaposition. The electric actuator 3 therefore has a thickness E limited by the thickness of the hydraulic distributor 11. The electric actuator is fixed to the body 19 of the hydraulic distributor on an interface 21 of the body constituting one of the minor faces of the body.

[0038] Referring in particular to the Figures 3-7a And 10-13the electric actuator comprises an electric motor 6, an electronic circuit 10 comprising a circuit board 24, a linear displacement output member 4 coupled to the valve slide 13, a reduction gear 8 comprising gear wheels 22 coupling the motor to the output member, and a housing 2 in which the electric motor 6, the electronic circuit 10 and the reduction gear 8 are mounted. The output member 4 is connected to, or integral with, a rack 5 arranged in the housing 2 of the electric actuator.

[0039] The motor 6 of the electric actuator is a closed-loop controlled brushless DC motor. Compared with a stepper motor used for actuating a hydraulic valve in conventional hydraulic controls, the use of a closed-loop controlled brushless DC motor makes it possible to transmit higher force peaks to the valve spool and to work more safely, in particular by having high reliability in positioning the output member of the electric actuator.

[0040] The hydraulic control 1 may comprise, for each hydraulic valve, a pre-stressed return spring 15. The valve spool is pushed by the pre-stressed return spring 15 which moves it into a fail-safe position (so-called "fail safe" position) when the hydraulic system fails. To overcome the force of the return spring 15 and ensure highly dynamic operation, the electric actuator must provide a high dynamic force. The choice of a closed-loop controlled brushless DC motor makes it possible to meet this requirement reliably, in an economical and compact configuration.

[0041] In a first variant, illustrated in the figures 1 And 2 , the return spring 15 is mounted in a housing in the body 19 of the hydraulic distributor 11.

[0042] In a second variant, illustrated in the figures 8 And 9, the return spring 15 is mounted at the interface between the body 19 and the electric actuator, in a housing 23 formed in the housing 2 of the electric actuator. The axis of the output member 4 of the electric actuator 3 comprises a coupling part 7a mounted in a chamber 27 of the hydraulic distributor in which the return spring 15 is mounted. The chamber 27 is closed by a cap 25 mounted on the body of the hydraulic distributor, the chamber being filled with hydraulic fluid. A seal 29 is arranged between an orifice in the wall of the cap 25 and the axis 7a of the output member to ensure sealing between the hydraulic circuit and the electric actuator. For the assembly of the actuator 3 and the distributor 11, the rack 5 is pre-assembled to the output member 4, and when fixing the electric actuator 3 to the hydraulic distributor 11, inserted into the housing 2 between the support bearing 79 and the pinion 62.

[0043] The output member 4 may be coupled to the valve spool 13 by means of a removable connection configured to absorb positioning tolerances, for example in the form of a ball joint. In this example, the output member 4 may comprise a partially spherical coupling portion 31 inserted into a housing 33 at the end of the valve spool. A play-compensating spring 29 prestressed in the housing 33 presses the coupling portion 31 against a stop in the housing in order to eliminate the positioning play in the transverse direction. T between the output member 4 and the valve slide 13.

[0044] The housing 2 of the electric actuator comprises a base 14 and a cover 16 which closes the open side of the base. The base 14 of the housing forms a volume inside which the motor 6, the reducer 8 and the electronic circuit 10 are mounted. The cover 16 and the base 14 can advantageously be made of an injected plastic material, the edge of the cover 16 being welded to the edge of the base 14, for example by ultrasonic or laser welding, in order to ensure a hermetic seal between the cover 16 and the base 14.

[0045] The motor 6 comprises a rotor 18 and a stator 20. The motor is in the form of a brushless DC motor.

[0046] In one embodiment, the rotor 18 comprises a magnet 30 forming a plurality of magnetic poles, for example a cylindrical magnet having a plurality of magnetized segments of alternating polarities arranged around the circumference of the cylinder. The rotor 18 may advantageously comprise a yoke 34 arranged coaxially within the cylindrical magnet, the yoke 34 being formed of a material with high magnetic permeability, such as soft iron.

[0047] In a preferred embodiment, the yoke 34 and the magnet 30 are mounted in a support 68 of overmolded plastic, the support comprising flanges 69a, 69b extending radially above the axial ends of the yoke 34 and the magnet 30. The outer diameter of the yoke 34 is slightly less than the inner diameter of the magnet 30, the clearance between these two diameters being in a range of 50 to 200 microns, configured to compensate for a difference in thermal expansion between the yoke 34 and the magnet 30. In order to maximize the magnetic efficiency and consequently the residual torque of the motor, the gap between the yoke 34 and the magnet 30 should be as small as possible while allowing sufficient clearance for differences in thermal expansion and also to allow easy assembly of the yoke 34 into the magnet 30.

[0048] Overmolding the radial flanges over the axial ends of the yoke 34 and the magnet 30 advantageously allows the magnet 30 to be secured to the yoke 34 with the smallest desired clearance without requiring the use of glue or other securing means between the yoke 34 and the magnet 30.

[0049] The support 68 may further comprise a pinion 40 secured to the support 68, for example advantageously formed from a plastic material injected at the same time as the support 68. The support 68 may be hollow in order to insert an axle 36, bearings 38 being mounted at the ends of the axle 36 in order to support the rotor in rotation in the housing 2.

[0050] The stator 20 comprises a magnetic armature 42 and coils 44 mounted on arms of the magnetic armature 42. The magnetic armature 42 is made of a material with high magnetic permeability such as soft iron. The teeth 50 of the magnetic armature 42 define a number of magnetic poles. The coils 44 are formed by conductive wires connected to electrical terminals 54.

[0051] The electrical terminals 54 may be formed from stamped parts.

[0052] In one embodiment illustrated in the Figure 15a , the pair of terminals 54 for the two ends of a wire 45 of a coil can be formed from a single stamped part overmolded by the plastic material supporting the armature 42 and the coils 44, a bridge 55 between the two terminals 54 then being cut after the overmolding operation or when the stamped part is still in the overmolding mold.

[0053] The terminals may also be inserted into the plastic material supporting the armature. The electrical terminals 54 may advantageously comprise a connection portion 57 to be crimped to the coil wire, allowing automated and rapid manufacture of the coils and their interconnection to the electronic circuit 10.

[0054] The terminals may advantageously comprise a part in the form of pins 53 oriented in an axial direction A configured to be inserted into complementary conductive holes of a circuit board 24 of the electronic circuit 10.

[0055] In one embodiment illustrated in the Figure 15b , the pins 53 are offset by a distance r in a radial direction in order to have a compact arrangement while ensuring sufficient distance between the pins for connection to the printed circuit.

[0056] The magnetic armature 42 and the coils 44 can advantageously be directly overmolded in the plastic material forming the base 14, including the electrical terminals 54 ready to be coupled to the circuit board 24.

[0057] The rotor 6 can be inserted axially into the stator which is directly integrated into the base of the housing.

[0058] The reducer 8 comprises gear wheels 22 comprising a first wheel 46 and a second wheel 48. The first wheel 46 comprises a toothed crown 58 engaging the pinion 40 of the rotor 18. An axle 59 supporting the rotation of the first wheel 46 is mounted at the ends in housings formed in the base 14 and in the cover 16. Similarly, the second wheel 48 comprises an axle 63 mounted at the ends of the housings formed in the base and the cover.

[0059] The axles 59 and 63, like the rotor 18 and the gear wheels 22 as well as the circuit board 24, can all be assembled in an axial direction A in the base 14 to simplify the assembly operations.

[0060] The second wheel 48 of the reducer 8 comprises a pinion 62 which engages the rack 5. The rack 5 may be supported at its back by a bearing 79 so that the rack 5 comprises a support on both opposite sides to guide them in the transverse direction T of linear movement of the output member 4.

[0061] With respect to the rotor 18 of the motor 6, the toothed crown 60 of the second wheel 48 is arranged on the other side of the circuit board 24 with respect to the magnet 30 of the rotor 18. The circuit board 24 advantageously comprises cut-out portions 74, 72, a first cut-out 72 allowing the axial passage of the circuit board 24 to partially circumnavigate the pinion 40 and the toothed crown 58 of the first wheel 46 which is arranged at the height of the circuit board. The circuit board 24 can therefore be arranged just above an axial end of the magnet 30 of the rotor 18, Hall effect position sensors 26 being arranged on the circuit board 24 above the magnetic segments 32 of the magnet 30.

[0062] The magnetic probes 26a, 26b, 26c, for example Hall effect sensors, may advantageously be arranged close to one another, the probes being in particular spaced apart by an angle α around the axis of rotation of the rotor of less than 60 degrees. In other words, the probes are arranged in an arc of a circle around the rotor of less than 60 degrees. In the example illustrated, there are three magnetic probes 26a, 26b, 26c, but in variants it is possible to have two, four, or more probes to detect the position and speed of the rotor. For a rotor formed by 5 pairs of poles, the probes 26a, 26b, 26c may in particular have an angle of 24 degrees between adjacent probes in order to form an electrical angle of 120 degrees.The arrangement of the magnetic probes 26a, 26b, 26c according to the embodiment of the invention described above makes it possible to reduce the size of the circuit board 24 and leave more space for the stator 20 and the reducer 8 in order to reduce the size, in particular in the axial direction A of the actuator. The magnetic probes 26 make it possible to detect the position and speed of the rotor 18 in a very compact and economical configuration.

[0063] The stator 20 of the motor comprises a magnetic armature 42, three coils 44 mounted on branches of the magnetic armature arranged asymmetrically around the rotor 18, and in particular arranged in an arc of a circle around the rotor 18 of less than 180 degrees. Poles of the stator on the opposite side of the coils 44 are formed by teeth 50 of the armature without coils, this making it possible to have a stator 30 of small diameter on the opposite side of the coils. The axis 59 of the first wheel 46 of the reducer 8 is mounted next to the part of the stator 20 without coils in order to have a small distance with the axis of the rotor 18 to reduce the diameter of the first wheel 46, for a compact configuration.

[0064] The teeth 50 may have different widths (in the direction of rotation of the rotor), for example a first series of teeth with a greater width than a second series of intercalated teeth as illustrated in the Figure 15a, or the 50 teeth may all be of identical width as shown in the Figure 15b .

[0065] The ring gear 60 of the second wheel 48 is disposed above the circuit board 24, the pinion 62 of the second wheel 62 extending through a cutout 74 of the circuit board to engage the rack 5 disposed below the circuit board 24. The second wheel 48 may advantageously comprise a position marker 64 disposed on a face of the ring gear 60 opposite the circuit board 24. A position detector 28 may be mounted on the circuit board 24 below the position marker 64. In an advantageous variant, the position detector 28 may be in the form of a Hall effect sensor and the position marker 64 may be in the form of a ring magnet, for example a segmented ring magnet allowing the Hall effect sensor to detect the movement of the second wheel 48.The second wheel 48 being directly coupled to the rack 5, the position detector 28 of the toothed crown 60 makes it possible to provide the position of the output member 4. The integration of the position detector 28 directly on the circuit board 24 makes it possible to have a particularly compact and economical arrangement while ensuring the reliability of positioning of the output member. In a variant, the position marker 64 and the probe can be optical. For example, the position marker 64 can comprise light and dark segments and the position detector 28 on the circuit board 24 comprises a light source and an optical sensor for detecting the passage of the segments.

[0066] The electronic circuit 10 may include capacitors 66 used in particular for filtering electrical interference. These capacitors 66 take up a certain volume and may be arranged on the circuit board 24 oriented towards the base 14 of the housing 2, on the same side as the rotor 18.

[0067] The electronic circuit 10 may be connected to an external control by a connector 12, the connector housing being integrally formed with the base 14 of the housing. Electrical terminals 78 of the connector 12 may be overmolded directly into the base 14 of the housing, the terminals 78 comprising connection portions in the form of axially oriented pins 81 for a press-fit type connection with conductive holes of the circuit board 24 when the latter is axially inserted into the base 14 of the housing during its assembly.

[0068] Advantageously, the overmolding of the stator 20 of the motor 6, the connection of the coils 44 of the motor, and the electrical terminals 78 of the connector 12 directly in the base 14 of the housing, also forming the bearings for the rotor bearings as well as the housings for the axes of rotation of the gear wheels in the base makes it possible to provide an economical and very compact actuator. The arrangement of the second gear wheel 60 of the reducer 8 above the circuit board 24, engaging the first gear wheel 58 below the circuit board 24, with the pinion 62 passing through a cutout in the board 24, makes it possible to have a small footprint in the axial direction A, while providing a large reduction, which makes it possible to use a brushless motor at high speed and providing a high residual torque.Furthermore, the arrangement of the motor coils as well as the position probes 26a, 26b, 26c of the rotor in a reduced arc of a circle, makes it possible to arrange the first gear wheel close to the rotor while keeping the axial height of the actuator low.

[0069] The electric actuator according to the invention is very compact and is notably characterized by dimension ratios (see figures 8 , 10, 11, 12 , 15 ) described below.

[0070] According to an advantageous aspect of the invention, the ratio e / E of the thickness e of the stator, including the winding thickness, to the thickness E of the electric actuator is greater than 0.45, the direction of measurement of the thickness being the direction of stacking or juxtaposition of the hydraulic valves forming the hydraulic control.

[0071] According to an advantageous aspect of the invention, the ratio L / E of the length L of the electric actuator 3 to the thickness EThe ratio of the electric actuator is greater than 2.5 and less than 4, the measuring direction of the length being orthogonal to the stacking direction of the hydraulic valves forming the hydraulic control and the operating direction of the valve drawer.

[0072] According to an advantageous aspect of the invention, the ratio H / E of the height H of the electric actuator 3 to the thickness E of the electric actuator is greater than 2 and less than 3.5, the measuring direction of the height being the operating direction of the valve drawer.

[0073] These advantageous ratios for providing a compact actuator are summarized in the following table: L / E H / E e / E >2.5 >2 >0.45 <4 <3.5

[0074] By way of illustration, examples of electric actuators according to advantageous embodiments of the invention may have the following dimensions: Dimensions in mm Actuator Stator Thickness (e) Ratios and differences Thickness ( E ) Length ( L ) height ( H ) L / E H / E e / E Ee 40 125 100 22 3.1 2.5 0.55 18 32 125 100 16 3.9 3.1 0.50 16 48 125 100 30 2.6 2.1 0.63 18 List of references in the figures

[0075] Hydraulic control 1 Hydraulic valve Hydraulic distributor 11 Body 19 Valve spool 13 Housing 33 Play compensation spring 19 Return spring 15 Hydraulic channels 17 Interface 21 Cap 25 Spring chamber 27 Seal 29 Actuator 3 Box 2 Base 14 Cover 16 Housing 23 (to receive the return spring) Output organ 4 Rack 5 Guide bearing 79 Axle 7 Coupling part 31 Spherical head Engine 6 Rotor 18 Magnet 30 Poles 32 Yoke 34 Axis 36 Bearings 38 Bearing Pinion 40 Support 68 (overmolding) flange 69 Stator 20 Magnetic armature 42 Teeth 50 Coil 44 Conductive wire 45 Electrical terminals 54 Bridge 55 Crimp connection part 57 Connection pins 53 Overmolding 61 Reducer 8Gear wheels 22 First wheel 46 Pinion 56 Crown gear 58 Axle 59 Second wheel 48 Crown gear 60 Position marker (magnet) 64 Pinion 62 Axle 63 Electronic circuit 10 Circuit board 24 cutout 72 (for first gear wheel) cutout 74 (for output pinion) Rotor position sensor 26 Magnetic probes (Hall effect) 26a, 26b, 26c Second gear position sensor 28 Capacitors 66 Connector 12 78-pin terminals 81

Claims

1. A hydraulic control (1) comprising at least one hydraulic valve, each hydraulic valve including a hydraulic distributor (11) and an electric actuator (3), the hydraulic distributor comprising a body (19) with hydraulic channels (17) and a valve spool (13) slidably mounted in the body (19), the electric actuator being fixed to said body and comprising a brushless direct current electric motor (6) capable of being controlled in a closed loop, the motor comprising a stator (20) and a rotor (18), the rotor comprising a magnet (30) defining a plurality of rotor poles and the stator comprising a magnetic armature (42) and a plurality of coils (44) mounted on the magnetic armature, an electronic circuit (10) including a circuit board (24), a linear displacement output member (4) coupled to the valve spool, a reduction gear (8) including gear wheels (22) coupling the motor to the outlet member, and a casing (2) in which the electric motor (6), the electronic circuit (10) and the reduction gear (8) are mounted, the gear wheels (22) including at least a first wheel (46) and a second wheel (48), the second wheel (48) being disposed on the side of a cover (16) of the casing (2) and the electric motor being mounted in the base (14) of the casing (2), the first wheel (46) comprising a crown gear (58) engaging a pinion (40) of the motor and a pinion (56) engaging a crown gear (60) of the second wheel (48), the circuit board (24) being disposed between the crown gear (60) of the second wheel (48) and the rotor magnet of the electric motor, the crown gear (58) of the first wheel (46) being disposed at the height of the circuit board, in a cutout of the circuit board.

2. The hydraulic control according to claim 1, characterized in that a ratio e / E of a thickness e of the stator, including the thickness of the winding, of the electric motor on a thickness E of the electric actuator is greater than 0.45, the thickness measurement direction being a stacking direction of the hydraulic valves forming the hydraulic control.

3. The hydraulic control according to claim 1 or 2, characterized in that a ratio L / E of a length L of the electric actuator on a thickness E of the electric actuator is greater than 2.5 and less than 4, the direction of measurement of the length being orthogonal to a stacking direction of the hydraulic valves forming the hydraulic control and a direction of actuation of the valve spool.

4. The hydraulic control according to claim 1, 2 or 3, characterized in that a ratio H / E of a height H of the electric actuator to a thickness E of the electric actuator is greater than 2 and less than 3.5, the direction of height measurement being the direction of actuation of the valve spool.

5. The hydraulic control according to one of the preceding claims, characterized in that the second wheel (48) comprises a position marker (64) disposed on one face of the crown gear (60) relative to the circuit board (24) and a position detector (28) is mounted on the circuit board (24) below the position marker (64).

6. The hydraulic control according to the preceding claim, characterized in that the position detector (28) is in the form of a Hall effect sensor and the position marker (64) is in the form of an annular magnet.

7. The hydraulic control according to one of the preceding claims, characterized in that the second wheel (48) of the reduction gear comprises a pinion (62) which engages a rack (5) connected to the linear displacement output member (4).

8. The hydraulic control according to one of the preceding claims, characterized in that the circuit board is disposed above an axial end of the magnet (30) of the rotor, magnetic probes (26a, 26b, 26c) being disposed on the circuit board (24) above the magnetic segments (32) of the magnet, the magnetic probes (26a, 26b, 26c) being disposed in an arc around the rotor at an angle (α) of less than 60 degrees.

9. The hydraulic control according to one of the preceding claims, characterized in that the magnet (30) of the rotor (18) is cylindrical in shape and a yoke (34) is disposed coaxially inside the cylindrical magnet (30), the yoke (34) and the magnet (30) being mounted in a support (68) made of overmolded plastic material, the support (68) comprising flanges (69a, 69b) extending radially above the axial ends of the yoke and the magnet.

10. The hydraulic control according to the preceding claim, characterized in that the support (68) comprises a pinion (40) integral with the support formed of an injected plastic material.

11. The hydraulic control according to one of the preceding claims, characterized in that the coils (44) are mounted on branches of the magnetic armature (42) disposed in an arc of less than 180 degrees around the axis of rotation of the rotor, an axis (59) of rotation of the first wheel (46) of the reduction gear being mounted next to a portion of the stator without coils.

12. The hydraulic control according to one of the preceding claims, characterized in that the motor comprises conductive wires of the coils connected to electrical terminals (54) formed of stamped parts inserted into or overmolded by a plastic material integrally forming the base of the casing and supporting the armature (42) and the coils (44).

13. The hydraulic control according to one of the preceding claims, characterized in that the electric actuator comprises a connector (12) for connecting the electronic circuit (10) to an external control, a casing of the connector (12) being formed integrally with the base of the casing (2), electrical terminals (78) of the connector being overmolded into the base of the casing (2) and comprising axially oriented connection portions for connection with the circuit board (24).

14. The hydraulic control according to one of the preceding claims, characterized in that it comprises a preloaded return spring (15) acting on the valve spool (13), the return spring being mounted at an interface between the body (19) of the distributor and the electric actuator, in a housing (23) formed in the casing (2) of the electric actuator.

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